The lug is the old sail of the Norsemen. There are two kinds of lugs, "dipping" and "standing."
The dipping lug has a great part of the sail beyond the mast, so that when a tack has to be made the sail has to be lowered, dipped round the mast and rehoisted.
The standing lug projects very little beyond this mast and does not require to be lowered when tacking.
Fishing boats are nearly all rigged with a dipping lug for the mainsail and a standing lug for the mizzen, and they have also a jib, while some of them carry topsails over the lugs.
Luggers may carry any number of masts, but as a rule they have two; some have a gaff mizzen. When the foot of the lug is lashed to a boom it is said to be "balanced."